1. Field of Invention
The present invention relates to flame nozzles of a device for gas pressure welding which heats reinforcing steel with oxy-acetylene flames, welds by applying pressure, and accessories that support and hold the nozzles.
2. Description of Related Art
In general, when a piece of reinforcing steel is welded to another piece of reinforcing steel, the connection has been accomplished using a device for gas pressure welding to insure sufficient strength of the connection joint. The gas pressure welding is carried out by abutting the end faces of each piece of reinforcing steel to be processed for welding together, and the abutting point is welded by heating while pressure is applied to the joint face. The nozzle used for the heating is configured to blow a combustion gas, such as acetylene gas. The tip of the nozzle is usually formed on a bifurcate conduit and the combustion flames from the tip hits along the radial direction of the reinforcing steel so that the flames heat a whole circumference of the reinforcing steel.
In the conventional nozzle, a conduit is formed in a curve, such as a ring-shape or a U-shape, so that the conduit surrounds the circumference of the reinforcing steel to be welded. The tips of the nozzle are arranged on the wall of the conduit so that flames blow out toward the central portion which is surrounded by the conduit. When the reinforcing steel to be welded is placed in the central portion of the conduit, plural nozzle tips are arranged in an equal angle along the periphery of the reinforcing steel so that the flames from the nozzle tips uniformly overlays the whole circumference of the weld point on the reinforcing steel. The number of the nozzle tips formed on the conduit is usually 4, 6, 8, . . . or 12 and the nozzle tips are arranged to uniformly heat the whole circumference of the reinforcing steel.
However, in the conventional gas pressure welding device, since the conduit on which the nozzles are provided and the nozzle tips are arranged is on a common plane, the plane formed by the flame blown out from the nozzles coincides with a cross section of the reinforcing steel. Accordingly, although the conventional nozzles can specifically heat the circumference of a cross section of the reinforcing steel along a line, the conventional nozzles can not heat a range of area broader than a certain width. Therefore, in the conventional gas pressure welding device, it is necessary to constantly swing the nozzles between a certain area along the axial direction of the reinforcing steel. Accordingly, a gas weld worker has to swing the conduit with nozzles along the axial direction of the reinforcing steel with his hand while he manages to position the reinforcing steel at the central portion. Thus his work always requires tension, and has a disadvantage that if the welder misses his target area, oxygen comes in to make oxidation in a flash, which will disqualify the weld during inspection.
When gas pressure welding reinforcing steel, workers must pay attention to various aspects of the heating work in which they are engaged. For example, workers must carefully prepare before starting the heating work, such as inspecting the end portions of the reinforcing steel for cracks and bends which yield damaging defects on the pressure welded spot, as well as inspecting the gas pressure welding device and its accessories, treating and processing of the end face of the reinforcing steel to be pressure welded, and installation of a pressurizing machine. Another aspect to pay attention to is the temperature and weather of the job site at the time when the work is carried out, because such factors as high temperature, cold temperature, strong wind, and rain or snow can also affect the job from the safety standpoint since the workers are handling high pressure oxygen and acetylene gases. Therefore it is an industry regulation that a gas pressure welding operation be carried out under the control of a qualified person. Therefore, the development of a flame nozzle which ensures secure welding work has been necessitated because the slight amount of carelessness can affect the quality the finished job on a large scale.